CS246186B1 - Hydraulic oils with viscosity indices up to 200 - Google Patents

Abstract

Hydraulic oils with high viscosity indices complying with the ISO/TC 28/SC 4 classification for the HV group and types 32, 46, 68 and 100, made from mixtures of two types of sufficiently deeply dewaxed high-pressure hydrogenates of vacuum distillates of Soviet pipeline crude oil and refining additives consisting of a shear-stable polymer viscosity modifier, an anti-wear and antioxidant additive, a rust inhibitor, an anti-foam additive and, if necessary, a lubricity additive.

Description

(54) Hydraulic oils with viscosity indices up to 200

Hydraulic oils with high viscosity indices complying with the ISO/TC 28/SC 4 classification for the HV group and types 32, 46, 68 and 100, made from mixtures of two types of sufficiently deeply dewaxed high-pressure hydrogenates of vacuum distillates of Soviet pipeline crude oil and refining additives consisting of a shear-stable polymer viscosity modifier, an anti-wear and antioxidant additive, a rust inhibitor, an anti-foam additive and, if necessary, a lubricity additive.

The invention relates to hydraulic oils with viscosity indices up to 200, meeting the quality parameters of oils of the HV group of the ISO/TC 28/SC 4 classification, made from high-pressure hydrogenates of vacuum distillates of Soviet pipeline crude oil, dewaxed to low solidification points, so that after the addition of a shear-stable polymer viscosity modifier (viscosity index) they have low viscosities at low temperatures and after the addition of other improving additives they also have satisfactory oxidation stability, corrosion protection, good anti-wear properties, low foaming, the ability to separate water and air and are shear-stable.

Hydraulic transmissions /drives/, in which liquids are used to transmit and regulate force based on the laws of hydraulics, are used where pressure multiplication is necessary or where precise and reliable regulation is required. Liquids used as a driving medium must also perform the function of lubrication, dissipate heat and protect the internal parts of the hydraulic system from corrosion. Their quality parameters /useful properties/ differ depending on the design, performance and working conditions of the hydraulic systems.

Hydraulic oils with high viscosity indices of the HV group of the ISO/TC 28/SC 4 classification are intended mainly for the drive and control of high-pressure mobile hydraulic machines that operate in a wide temperature range. These operating conditions also impose requirements on their properties.

The basic criterion is the viscosity of the oil. When choosing the viscosity, not only the basic factors that influence it /speed, load, temperature/ must be taken into account, but also the requirements of individual parts of the hydraulic system, which have different designs. Therefore, the classification

ISO divides hydraulic oils according to kinematic viscosities measured at 40 °C into seven groups: 10, 15, 22, 32, 46, -68, 100 mm . s with a T range of 10%.

Oils used as fillings for hydraulic systems operating at high pressures over a wide temperature range, i.e. mainly systems operating outdoors, must have sufficient fluidity (pumpability) even at the lowest operating temperatures to enable pump start-up and at the highest temperatures their viscosity must not fall below the limit required to ensure the lubricating function and volumetric efficiency of the hydrogenerator. Such oils must therefore have sufficiently high viscosity indices and low pour points, which are generally achieved by the addition of a polymer viscosity modifier (viscosity index) and a depressant, mainly of the polymethacrylate type. Since the polymer can depolymerize to a greater or lesser extent under the effect of shear stress and temperature and thus lose its thickening ability, it is necessary to use a polymer viscosity modifier (VI) with high shear stability. However, to achieve sufficient fluidity of the hydraulic oil at low temperatures, the base oil itself, from which it is made, must have satisfactory rheological properties, which are determined by its chemical composition, or rather the content of solid paraffins, and it is therefore necessary that the content of solid paraffins is reduced to an acceptable limit by sufficient dewaxing, which is controlled by the maximum permissible pour point of the oil.

Low oil viscosity may not ensure perfect lubrication and suppression of friction surfaces due to high pressures. Hydraulic oils therefore commonly contain an anti-wear additive, either of the ash type /mainly zinc dialkyldithiophosphate with alkyls Cg to Cg, which also acts as an oxidation and corrosion inhibitor/ or of the ashless type /e.g. aryl phosphate/ and may also be equipped with a lubricating additive /e.g. a suitable fatty acid ester/ in order to achieve smooth function, mainly of the control elements.

Recently, there has been a tendency to equip high-quality hydraulic oils for certain types of hydraulic systems with detergent-dispersant additives to ensure the cleanliness of the system with long-term oil fillings and to achieve binding of free moisture. The choice of a suitable type or combination of types of detergent-dispersant additives and its amount in the oil is mandatory if the foaming and emulsification of the oil is not to be significantly impaired.

For the system to function properly and to achieve high efficiency, it is important that the propellant fluid is as incompressible as possible. This depends mainly on the content of dissolved air or other gases that increase the compressibility of the fluid. Therefore, hydraulic fluids do not have to have the ability to quickly separate air or gases. This ability depends not only on its viscosity, but also on its chemical composition, or the content and composition of refining additives. The ability to separate air is also related to the degree of foaming of the oil, which should be as low as possible, which can be achieved to a large extent by an anti-foaming additive /most often of the polymethylsiloxane type/, which hydraulic oils therefore also commonly contain.

It is required that the service life of the oil filling of the hydraulic system is as long as possible, i.e. that the oil has a sufficiently high thermo-oxidative stability. This is determined both by the chemical composition of the base oil and by the choice of the type and content of the antioxidant additive, which is why quality hydraulic oils always contain it. /In oils containing zinc dialkyldithiophosphate, this additive acts as an oxidation inhibitor, ashless antioxidants of the alkylphenol or aromatic amine type are added to ashless hydraulic oils,/

The presence of a small amount of moisture in the oil cannot be ruled out in any hydraulic system. Since these oils are mostly deeply refined, which as a result, and especially at low viscosity, do not have sufficient ability to protect metal surfaces from rusting, they regularly also contain a rust inhibitor. /Such rust inhibitors can be oil-soluble petroleum or synthetic alkylarylsulfonates of various metals, mainly calcium, low-molecular succinimides, N-acyl derivatives of sarcosine, etc./

The hydraulic oil should be compatible with the rubber seals used in the hydraulic system. It should not cause excessive swelling or shrinkage of the rubber. This ability is determined not only by the nature /chemical composition/ of the oil, but also by the chemical composition of the rubber. In practice, the choice of the type /composition/ of rubber is adapted to the hydraulic oil used.

Hydraulic oils are mainly produced from petroleum selection raffinates, mainly of cyclanic character, but synthetic oils (mainly ester and polyalphaolefin) are also used.

We have found that very high-quality hydraulic oils with high thermo-oxidative stability and good thermal properties at low temperatures, which also meet other required quality parameters for oils of the HV group of the ISO/TC 28/SC 4 classification, after adding the necessary refining additives in sufficient quantities, can be produced from sufficiently deeply dewaxed high-pressure hydrogenates, i.e. petroleum oil raffinates of vacuum distillates of Soviet pipeline crude oil with high viscosity indices, obtained by high-pressure hydrocracking process at a pressure of about 15 MPa, a temperature of about 400 °C on a catalyst containing nickel and tungsten sulfide on an acidic carrier of the SiOj.A^Og type.

The essence of the invention are hydraulic oils with high viscosity indices of the HV group and types 32, 46, 68 and 100 according to the ISO/TC 28/SC 4 classification, the quality parameters of which comply with this classification, made from base oils consisting of mixtures of two high-pressure hydrogenates of vacuum distillates of Soviet pipeline crude oil with defined quality parameters, the ratio of which in the mixtures is chosen so that after the addition of refining additives the resulting oil has the required viscosity at 40 °C and from refining additives, namely a polymeric viscosity modifier /viscosity index/ with high shear stability, which also acts as a pour point depressant, an antioxidant of the zinc dialkyldithiophosphate type with C ₃ to C8 alkyls, which simultaneously acts as an anti-wear additive and corrosion inhibitor, a rust inhibitor and an anti-foam additive.

Example 1

Hydraulic oil HV 32 was prepared according to ISO/TC 28/SC 4 with the composition:

/with a viscosity of 3.55 mm ² .s ^-1 at 100 °C, with VI 79, with a freezing point of -21 °C, with a flash point /OK/ of 168 °C and with oxidation stability according to CSN 65 6235 /100 °C, 40 11, 5 1 air/h/

High-pressure hydrogenate I

- acidity number after oxidation 0.15 mgKOH/g, sediment 0.01% wt; 92,049 % mass Polymer viscosity modifier of the polymethacrylate type, stable in shear with M _w 150,000 /Empicryl 6052/ 7.0 « mass Zinc dialkyldithiophosphate with alkyls - Cg /Multadit OB/ 0.8 % mass Calcium alkylaryl sulfonate /Nasul BSN/ 0.15 % mass Polymethylsiloxane /Lukoil MS 200/ 0.001 « mass

The prepared oil had the following quality /useful/ parameters:

Kinematic viscosity /mm ² .s ^-1 / at 40 °C 31.5

100°C 6.74

Viscosity index 180

Dynamic viscosity /mPa.s/ at -10 °C 410

-20°C 1,450

Blowing point, °C -54

Flash point /OK/, °C 174

Water content 0

Demulsification characteristic /ml after 30 min/ /oil-water-emulsion/ 40-40-0

Foaming capacity /ml/ at 24 °C 110/0 °C 50/0 °C after 93 °C 10/0

Air separation /min/°C/ 6/50

Acid number, mg KOH/g 0.93

Copper corrosion /3 h/100 °C/ 1 a

Oxidation test according to ČSN 65 6235 /140 °C, 48 h, 5.1 air/h,

Cu-catalyst/:

Viscosity gain at 50 °C +4.2

Dsad content after test, % wt. 0.01

Effect on rubber 1,078 /100 °C, 72 h/, % vol. +4.45

Vickers pump test:

Stator weight loss, mg 122 lamellas, mg 5

Shear stability /DIN 51 382/, oil viscosity decrease at 100 °C after 30 cycles, % -2.1

Example 2

Hydraulic oil HV 46 was prepared according to ISO/TC 28/SC 4 with the following composition:

High-pressure hydrogenate I with properties as in example 1 54.299 wt. %.

High-pressure hydrogenate II /with a viscosity of 7.22 mm ² .s ^-1 at 100 °C, with a VI of 95, with a pour point

-26 °C, with a flash point /OK/ 212 °C and with oxidation stability according to

ČSN 65 6235 /under conditions as for VT-hydrogenate 1/ 5 acidity number after oxidation 0.2 mg KOH/g, sediments 0.02% wt./ 36.00% wt.

Polymer viscosity modifier of the shear-stable polymethacrylate type with M _w 150,000 /Empioryl 6052/ 8.75 wt. %.

Content of other same ingredients as in example 1 0.951% by weight

The prepared oil had the following quality /useful/ parameters:

Kinematic viscosity /mm ² .s ^-1 / at 40 °C 49.8

100 ^eC 9.36

Viscosity index 178

Dynamic viscosity /mPa.s/ at -10 °C 960

-20°C 2,400

Freezing point, °C -48

Flash point /OK/, °C 191

Water content 0

Demulsification characteristics /ml after 30 min/ 40-40-0

Foaming capacity /ml/ at 24 °C 10/0 °C 70/0 °C after 93 °C 0/0

Air separation /min/°C/ 11/50

Acid number, mg KOH/g 0.93

Corrosion on the metal /3 h/100 °C/ 1 a

Oxidation test according to ČSN 65 6235:

Viscosity gain at 50 °C +6.7

Sediment content after test, % wt. 0.03

Effect on rubber 1,078, % vol. +0.47

Vickers pump test:

Stator weight loss, mg, laminations, mg

Shear stability /DIN 51 382/, viscosity decrease at 100 °C after 30 cycles by %

Example 3

2.2

Hydraulic oil HV 68 was prepared according to ISO/TC 28/SC 4 with the following composition:

High-pressure hydrogenate I as in Example 1 35.950% by weight.

High-pressure hydrogenate II as in Example 2 53.949 wt. %.

Polymer viscosity modifier of the shear-stable polymethacrylate type with M _w 150,000 /Empicryl. 6052/ 9.15 wt. %.

The content of the other same additives as in Example 1 is 0.951% by weight.

The prepared oil had the following quality /useful/ parameters:

Kinematic viscosity /mm ² .s ^-1 / at 40 °C 100 °C

Viscosity index

66.3

11.7

175

Dynamic viscosity /mPa.a/ at -10 °C -20 °C 1,440 4,500 Freezing point, °C -47 Flash point /OK/, °C 198 Water content 0 Demulsification characteristics /ml after 30 min/ 40-40-0 Foaming capacity /ml/ at 24 °C 15/0 93°C 80/0 24°C after 93°C 5/0 Air decidivoat /min/°c/ 10/50 acid number, mg KOH/g 0.95 Corrosion on copper /3 h/100 °C/ 1 and Oxidation test according to ČSN 65 6235: Viscosity gain at 50 °C +7.1 Content of sediments after the test, % by weight. 0.03 Effect on rubber 1,078, % vol. +0.10 Vickers pump test: Stator weight loss, mg 64 lamella, mg 2 Shear stability /DIN 51 382/, viscosity drop at 100 °C after 30 cycles by % 2.7 Example 4 Hydraulic oil HV 100 according to ISO/TC 28/SC 4 has been prepared with the composition: High pressure hydrogenate I as in example 1 13.329% by weight High pressure hydrogenate II as in example 2 75.520% by weight Polymer viscosity modifier of the polymethacrylate type, stable in shear with 150,000 /Emplcryl 6052/ 10.2% by weight Content of other same ingredients as in example 1 0.951% by weight The prepared oil had the following quality /useful/ parameters: Kinematic viscosity /mm^.s ^-1 / at 40 °C 96.4 100°C 15.6 Viscosity index 172 Dynamic viscosity /mPa.s/ at -10 °C 2,050 Freezing point, °C -46 Flash point /OK/, °C 205 Water content 0 Demulsification characteristics /ml after 30 min/ 40-88-2 Foaming capacity /ml/ at 24 °C 17/0 93°C 82/0 24°C after 93°C 7/0 Air decidivoat /min/°C/ 9/75 acid number, mg KOH/g 0.92 Corrosion on copper /3 h/100 °C 1 and

Oxidation test according to ČSN 65 6235:

Viscosity gain at 50 °C +8.1

Sediment content after test, % wt. 0.03

Effect on rubber 1,078, % vol. -0.35

Vickers pump test:

Stator weight loss, mg 47 laminations, mg 1

Shear stability /DIN 51 382/, viscosity drop at 100 °C after 30 cycles 3.2

Claims (2)

SUBJECT OF THE INVENTION 1. Hydraulic oils having a viscosity index of up to 200 of the HV group and types 32, 46, 68 and 100 of the ISO / TC 28 / SC 4 classification, characterized in that they consist of base oils consisting of mixtures of two types of high pressure hydrogenated vacuum distillate hydrogenates with a viscosity of 2.5 to 5 mm ² .s ¹ at 100 ° C, with a viscosity index of min. 70, with pour point max. -12 ° C, with flash point / OK / min. 165 ° c, and with satisfactory oxidation stability according to ČSN 65 6235 and heavier hydrogenate with viscosity 5.5 to 7.5 mm ² .s ¹ at 100 ° C, with viscosity index min. 90, with pour point max. -14 ° C, with flash point / OK / min. 195 ° C and with similar satisfactory oxidation stability to that of the lighter hydrogenate, in which the ratio of lighter to heavier hydrogenate is selected such that after addition of the upgrading additive the resulting oil has the desired kinematic viscosity at 40 ° C, from 6 to 14 wt. % of a shear-stable polymethacrylate type polymer with a M 100,000 to 400,000, from 0.6 to 1.0 wt. % anti-abrasion and antioxidant additives, preferably zinc dialkyldithiophosphate with C8 -C8 alkyls, from 0.1 to 0.5 wt. % rust inhibitor, preferably oil soluble calcium alkylarylsulfonate, and from 0.001 to 0.01 wt. anti-foaming agents, preferably polymethylsiloxane. 2. Hydraulic oils according to claim 1, characterized in that they contain a lubricant, preferably a higher alcohol or a fatty acid having a carbon number of min. 10 or an ester thereof in an amount of 0.5 to 5.0 wt.